Good question thanks. From the Gimeno et al. (2014) paper and others, atmospheric rivers seem to only form when a certain set of conditions come together associated with formation of a fast moving low level jet and enhanced humidity ahead of the cold front in the strongest cyclones under certain conditions of atmospheric stability/instability i.e. frontal convergence forces humid air to rise and the jet then transports it away to join the wider global-scale circulation across the oceans. They then lose much of their water vapour and energy due to uplift on meeting hills and mountains. Typically the ‘flow’ seems to persist for about a day but the strongest can last two days or more.
Can you give us any of the physics Kevin? What causes the extraordinary uptake of water and why doesn't the 'river' disperse?
Good question thanks. From the Gimeno et al. (2014) paper and others, atmospheric rivers seem to only form when a certain set of conditions come together associated with formation of a fast moving low level jet and enhanced humidity ahead of the cold front in the strongest cyclones under certain conditions of atmospheric stability/instability i.e. frontal convergence forces humid air to rise and the jet then transports it away to join the wider global-scale circulation across the oceans. They then lose much of their water vapour and energy due to uplift on meeting hills and mountains. Typically the ‘flow’ seems to persist for about a day but the strongest can last two days or more.